PROJECT SUMMARY/ABSTRACT Studies in pediatric blood disorders provide an important paradigm for understanding the fundamental mechanisms regulating hematopoiesis. Unlike adult hematologic disorders, many pediatric diseases result from intrinsic genetic defects that control blood cell development or function. Understanding remains incomplete on the molecular pathogenesis of most of the hematologic diseases in children. At UCLA, we have a tremendous resource of interdisciplinary investigators whose research focuses on a wide spectrum of topics related to developmental hematology. Given the declining number of physician-scientists in Pediatric Hematology, a training program in Developmental Hematology is critical to produce the cadre of investigators who will continue to advance the field. Therefore, we propose a unique training program that focuses specifically on pediatric hematologic diseases by integrating a variety of disciplines, including molecular and cellular hematopoiesis, alternative organism models, stem cell transplantation and gene therapy, hemostasis and thrombosis, transfusion medicine, novel technologies (genomics, proteomics, gene editing, etc.), hematologic malignancies, therapeutics, and bioinformatics. In this application, we seek funding for 4 postdoctoral fellows per year for 5 years. The fellows will be either recent recipients of MD, MD/PhD, or PhD degrees undergoing postdoctoral training. We will emphasize recruitment to reflect the gender, racial, and ethnic diversity of our nation. Trainees will have the opportunity to develop research in one of the 22 faculty member's laboratories that bridge 12 Departments, providing trainees access to the incredibly diverse academic assets across the UCLA campus. The mentoring faculty have active and productive research programs and multiple mutual collaborations and publications, providing an ideal training environment. Trainees may also participate in an exchange program established with the NHLBI-funded T32 program at the University of Michigan (HL007622) to gain deeper knowledge of either hemostasis/thrombosis or hematopoietic stem cell transplantation, two academic strengths of their program (UM trainees may come to UCLA for training in cell and gene therapy). Trainees will be selected from a large pool of postdoctoral fellows based on their academic and research achievements. Appointments will be for 1-2 years, the second year appointment dependent on documented productivity. Trainees will take a required course on Developmental Hematology and receive training in principles of human subject research and the responsible conduct of research through courses in research ethics. They will participate in journal clubs and attend seminars and lectures related to pediatric hematology, stem cell biology, immunology and clinical research. Trainees will meet with a Scholarship Oversight Committee every 6 months to monitor progress and productivity. We will utilize the strengths of UCLA, including the breadth and depth of investigators across many disciplines, to train future researchers and leaders in the field of Pediatric Hematology.